Our crew breaks down the red tide events and harmful algal blooms happening across South Florida’s waterways…
Guest Post by Paola Espitia, M.S.
Over the passed few weeks, we’ve noticed mats of green slime collecting on the sea walls, clumps of dried green patches floating nearshore, and pools of tiny green dots in the canals along our kayak routes. It’s algae season and when you spend as much time on water as we do, you pick up on changes that happen to the environment around you.
What are red tides and other harmful algael blooms?
A naturally occurring red-brown algae called Karenia brevis is responsible for red tide events on Florida’s southwest coastline. When their populations explode, they turn salty coastal waterways red and produce biotoxins that lead to fish kills, respiratory irritation, and in the death of sensitive species like sea turtles and manatees.
Another naturally occurring microorganism is the photosynthetic bacteria, cyanobacteria (formerly known as blue-green algae). As some of the oldest organisms on our planet, cyanobacteria produced the oxygen that gave way to the livable atmosphere we have today. Found locally in freshwater and brackish lakes, rivers, canals, and estuaries, cyanobacteria also contain biotoxins that can cause harm in high concentrations.
What causes harmful algal blooms?
Every summer, with the warming of temperatures and abundant sunlight, algal populations begin to grow. With the onset of summer rainstorms, excess fertilizers and pollution from agricultural lands, residential communities, and outflows wash into waterways adding nitrogen and phosphorous into the system. The excess nutrients fuel the growth of algae and a bloom occurs.
Why does it matter now?
When Florida’s naturally occurring red tide event is fed by the excess cyanobacteria coming from polluted agriculture, rural and urban lands around those systems, we see a disruption in the balance of the entire ecosystem. Lake Okeechobee, once healthy enough to flush harmful algae blooms from rivers and estuaries, is now coated with its own layer of cyanobacteria, adding to the problem with each discharge – a practice used by the U.S. Army Corps of Engineers to release water and protect the 730-square mile lake’s aging dike.
Although the event is naturally occurring, this year there is an unusually persistent red tide event on the southwest coast of Florida spanning over 100 miles of shoreline and reaching offshore to at least 40 miles. The magnitude of this red tide event is so grand that it is being swept into the Gulf of Mexico’s Loop Current, around the south end of the state and up the east coast of Florida to Palm Beach County where the Gulf Stream is at its closest to shore. It’s killing marine life and spoiling our coastline along the way.
Why should we care?
Red tide produces a biotoxin that has harmful effects on marine life and can cause eye irritation and respiratory issues in humans when airborneairborn. Depending on the species of freshwater cyanobacteria and the type of toxin it produces, it too can cause health issues including kidney and liver damage.
What can we do about it?
Although no harmful algal bloom advisories are in place for Broward County, in areas where there is high algal cover, toxins can be concentrated so it’s best for you and your pet to stay clear.
Here are ways you can keep unwanted nitrogen and phosphorous out of our waterways:
As water people, running a water business, we care about the health of our waterways. Thankfully, there are no reported health issues related to harmful algal blooms in Broward County but we will be keeping a close eye on this blooming issue so that we can all be informed, environmentally responsible Floridians.
Paola Espitia is a Fort Lauderdale-based Marine Conservationist and Blue Moon Adventures Tour Guide who speaks, teaches, and consults on the importance of connecting to and caring for our waterways. Each week, she interviews Wavemakers inspiring positive change for our blue backyard in a Facebook Live interview series called, Conversations by Water. Follow her work on Instagram and Facebook at @olapicreative